1. Field of the Invention
The present invention generally relates to means for opening microcentrifuge and test tubes (hereinafter referred to as "micro" tubes) and, more particularly, is concerned with a micro tube cap opening device having a tube holder for receiving and holding the tube and a slidable lifting bar on the tube holder for lifting the cap off the tube.
2. Description of the Prior Art
Micro tubes are small plastic tubes having a tube body capable of holding only a small amount of a liquid. Such tubes typically have a lid or cap which is attached to the tube body by a hinge strip and fits into an open upper end of the tube body by an interference fit. The interference fit of the cap with the upper end of the tube body tends to be quite snug in order to be liquid tight. The snug fit of the cap in the tube body upper end makes the cap difficult to remove therefrom and thus open in order to gain access to the contents inside the tube body.
A significant degree of risk of splashing or spilling the contents of a tube exists due to the force required to overcome the level of resistance created by the high coefficient of friction between the cap and the upper end of the tube body. This can be especially hazardous if the contents of the tube is toxic or infectious or has as part of the contents a radioactive isotope, such as one used as a marker for identification purposes. If the contents splashes or spills out of the tube, a person holding the tube is at risk of coming in contact with these substances.
Further, whenever radioactive materials are spilled, a substantial amount of paper work and reporting of the incident is required, irrespective of the level of radiation or of where the accident occurred. The health risk and extra work associated with spills are undesirable.
Also, some of the smallest tubes have volumes of two milliliters or less and are approximately one half inch in diameter and one half inch in length. The small size of these tubes makes them particularly difficult to handle. Manually opening the smallest tubes can be a fatiguing process, especially if the person must repeat the process many times over, as is often the case. Typically, the person employs both hands, one hand to hold the tube body and the other hand to open the cap of the tube. Yet, the person should have one hand available for pipetting liquids into and from the tube, while holding and opening or closing the tube. Efficient operation of a pipette is generally not achievable if the person must use both hands to manipulate the tube.
Devices have been developed for use in opening the caps of micro tubes. A representative example of a device is the one disclosed in U.S. Pat. Nos. 4,683,782 and 4,858,502 to Warburg. The Warburg device is a hand-held opener having a handle and a base at one end of the handle with a recess shaped to accept a lip projection of the cap on the tube. The Warburg opener may be actuated by a free hand of the person to remove the cap from the tube body. However, the Warburg opener requires that the tube body be disposed in a well of a separate tube rack or held by the other hand of the user. Thus, while the Warburg opener may be satisfactory in use under the specific conditions for which it was designed to function, it does not seem to provide an optimum solution for the problems at hand.
Consequently, a need still exists for an innovation which provides a more effective solution to the aforementioned problems in the prior art and without introducing any new problems in place thereof.